Manually Coded English (MCE), on the surface, looks the least like a natural signed language (e.g., American Sign Language, ASL), and therefore provides us with a prime target to test whether the structure of a spoken language can be successfully incorporated into the signed medium. This is especially relevant as the typology of MCE differs strikingly from ASL in how a bound morpheme affixes to a root (linear vs. non-linear). Although the predominantly linear nature of MCE morphology represents the structure of the English language, this does not necessarily mean that such morphophonological structure in the visual/gestural mode will be real and meaningful to deaf children. The recent introduction of MCE as a first/native language of deaf children represents a unique opportunity to investigate the learnability questions involved as well as questions related to effective use. Research has pointed out the special role of natural languages and their ability to be tuned to the learning mechanism of children, thus the naturalness of MCE may be, in part, determined by deaf children themselves. More importantly, the artificial nature of MCE, the language learning process of deaf children, and how these children cope with MCE may provide insight into two crucial areas: 1) linguistic creativity and its contribution to the development and use of natural language, 2) innate predisposition in regard to how natural signed languages should work. Thus the typological difference between ASL and MCE, specifically the type of affixation (linear vs. non-linear) will be systematically examined in MCE acquisition and use among deaf children as well as the segmentation of the sign structure involved. This area of investigation is vital pertaining to MCE as a sign system as many deaf children are being exposed to MCE as their sole linguistic input. The study outlined aims at understanding the role of modality in the development and use of language.